1. Field of the Invention
The present invention relates to a method of reducing computational demand for image tracking, in particular relates to a method capable of reducing the amount of image data to reduce computational demand, system requirement, and implementation costs.
2. Description of Related Art
A conventional way for operating transitional hoisting crane, for example, an overhead crane, used to utilize manual control levers or buttons by operator. However, the manual control is deficient to adjust the position and the movement speed of the overhead crane accurately to fulfill precision requirements. One of conventional way for operating transitional hoisting crane is by automatic control which drives the overhead crane to a predetermined position with setting coordinates through controlling circuit and calculating unit. Taiwan patent number I279389 disclosed a crane that includes a movement control unit, an encoder, and a GPS (Global Positioning System) connecting to a remote central computer with wireless device to receive the command from the remote central computer for moving the crane to a designated position through the encoder and the movement control unit.
Although the method of automatic control for driving server motor by computer encoder as disclosed above improved the accuracy of overhead crane operation, however, the problem existing in both manual control and automatic control is the offset occurred between the load and the overhead crane due to inertia of the load and flexibility of the wire during the movement of the overhead crane. The offset further causes a swing of the load to lead to an abnormal movement of the overhead crane with industrial accident such as the load dropped or collision. Therefore, it is desirable to protect the hoisted load from over swing during the movement.
The inventors of the present invention are currently researching in the field of monitoring the position of the load and the overhead crane by real time image tracking and take the displacement of the load and the overhead crane as parameter for controlling transitional hoisting crane to diminish the swing of the load. However, the conventional image processing capacity is deficient in performing the method aforementioned.
FIG. 1 shows a swing of a hoisted load occurred during movement operation, wherein the load B produces displacement x1, y1, and z1 along X-axis, Y-axis, and Z-axis with respect to the hoisting position A. According to the research of the inventors of the present invention, real time image tracking provides parameter for controlling transitional hoisting crane to diminish the swing of the load. In accurately manage the displacement variation between the load B and the hoisting position A, a plurality of cameras are installed for receiving a plurality of images of each plane to obtain the displacement of the load B relative to the hoisting position A in the three-dimensional space respectively, and calculate in real time the images taken from at least two planes that vary in the three-dimensional coordinates.
Furthermore, the conventional real time image tracking system uses expensive, high-speed, and high-resolution cameras to reach an immediate and precise effect of image tracking. As a result, not only the cost of equipment acquisition is increased, but also a high performance and high memory capacity and processing unit is required for increasingly computational demand of data processing and transmission.
Therefore, there is a need in the art to provide features for image tracking and reducing the amount of image data to resolve the technical difficulties in data processing.